thompson



March 8, 1932.

L. W. THOMPSON ELECTRICAL REGULATOR Filed Aug. 28, 1930 l6 5 l 8 H Inventor": v Louis W. Thompsbn,

His Attorney human. 8, 1932 UNITED ,s' rEs PATENT oi-Pics,

LOUIS w. rnolarson, or'scnEnEc'rADY, NEW YORK, assmnon 'ro ennnmumc'mrc COMPANY, A CORPORATION OF YORK mnc'rmcar. naouna'roa Application fled August 28, 1980. Serial- Ko. 478,468.

My invention relates to electrical regulators, andparticularly to improvements in rheostatic type regulators which are provided with auxiliary quick response regulating means.

It is an object of my invention to provide a new and im roved-electrical regulator which is characterized by ruggedness and quick action.

It is another object of my invention to provide a rheostatic regulator, which hasaux to which circuit 1 is connected, and a field winding 4 which is energized from thearmwture 5 of a shunt wound exciter 6, whose shunt field winding Thus in circuit therewith a fixed regulating resistance 8 and a variable rheostatic resistance 9. As shown by way of example, resistance 9 is varied by a rheostat arm 10, which 'slides thereover and which is in contact with a conducting bar 11. The. arm 10 is supported by a nut 12, which is in threaded engagement with the threaded extension 13 of the shaft of the armature'14 of a small. reversible electric motor. Reversal of this motor is secured by selectively energizing its oppositely wound field windings 15 and 15' by means of a pair of contactors 16 and 17. These contactors, when'energized,

complete a circuit-from a power supply cir- I cuit 20 through one or the other of the field windings, and the armature in series. Contactors 16 and 1'7'have their energizing circuits, completed through a pair of limit switches 21 and 22 respectively, these limit the nut 12 whereby their circuits are opened whenever nut 12 reaches either extreme limit of its travel.

As the small operating motor possesses 1 considerable inertia, and as there is always more or less friction in motor-operated rheostats of the type just described, such devices are relativel slow acting, and consequentl ithas been ound desirable to provide add1- tional means for producing quick changes in the value of the regulating resistance 1n the exciter field circuit. For this purpose contactors 18. and 19 are provided and arranged to control circuits for short-circuiting resistances 9 and 8 respectively.- Contact0r'19 being arranged normally to short-circuit resistance 8, while contactor 18 normally maintains the short-circuit around resistance 9:

open. V

For controlling contactors '16, 17, 18, and

19 I provide a circuit controller comprisin contacts 24 25, 36, and 37 which aremounte' on a movable element 30. by nieans of suporting members 28, 29, 39, and 40. I Memers 28 and 29 are resilientandthe contacts are so arranged that upon movement of member 30 in either direction contacts 24 or engage a rotatable cooperating cam contact 26 before either contact 36 or 37- engages a rotatable cooperating contact 38. These contacts are also all insulated from each other/by the insulating material shown on element 30. Member is mounted on an arm31, which connects to a device which responds to changes in the voltage in circuit 1. Any suit-.

able device operating in this manner may be used, the device illustrated being a three phase torque motor 32, whose windings are connected tothe three conductors of circuit 1 through three current. limiting resistors 33 and three adjustable resistors 34. A sin le operating lever 35 is shown for adjusting t e resistors 34 simultaneously.

element 30are in engagement with their 00- operating rotating contacts, while if the volt- The torque motor is so connected, and the l age of circuit '1 rises above normal an unswitches being actuated by a projection 23 on balanced'counterclockwise torque is produced, 1

thereby moving member 30 downwardly, and causing contacts and 37 to move toward their respective cooperating contacts, while if the voltage of circuit 1 falls below normal 1 an unbalanced clockwise torque is produced thereby causing contacts 24 and 36 to move upwardly toward their cooperating contacts 26 and 38 respectively.

A shaft 41, on which are fastened the rotatable contacts 26 and 38, is arranged to be rotated at a uniform speed by any suitable means, the means shown being a small, singlephase, self-starting synchronous motor 42, of the type commonly used in electric clocks. This motor may be energized from any suitable source, and as shown it is energized from one of the phases in circuit 1 through a suitable step-down transformer 43.

. To dampen the motion of arm 31, a suitable retarding means such as the device 44 is employed. This device is the equivalent of an ordinary dashpot and consists of a vane mov ing in a heavy viscous liquid, such as heavy oil. 1

Although I have shown my invention as I applied to the regulation of the voltage of a three-phase alternating current circuit, it will be obvious to thoseskilled in the art that my invention is not so limited, and that'any suitable means for moving arm 31 up and down with variations from normal of any one of a number of operating conditions to be regulated might be employed without departing from my invention in its broader aspects. It will also be obvious to those skilled in the art that it is not necessary to use an exciter, and that the regulating resistances might be connected in the field circuit of the regulated dynamo-electric machine if desired, although it is usually desirable to employ the exciter as in such case the current which the regulator must handle will be much smaller than if no exciter is used.

The energizing circuits for contactors 16 and 17 are from one side of supply circuit 20 through limit switches 21 and 22 respectively, through the contactors to movable contacts 25 and 24 respectively, thence through a rotatable cam contact 26, shaft 41, rotatable conducting member 27 to the other side of circuit 20. The energizing circuits for contactors 18 and 19 are from one side of the circuit 20 to the contactors, through contacts 36 and 37 respectively to rotatable conducting member 38. thence through shaft 41 to rotatable conducting member 27, and thence to the other side of circuit 20.

The operation of the illustrated embodiment of my invention is as follows. With the voltage of circuit 1 normal, movable element 30 will be in the mid-position, and contactors 16, 17, 18, and 19 will be deenergized resistance 8 will be short-circuited and resistance 9 will be of the proper value to give the excitation necessary to produce normal voltage under the circuit conditions existing at this time. If now circuit conditions change in a manner to cause the voltage of circuit 1 to rise torque motor 32 will cause movable element 30 to move downwardly, thereby causing an intermittent engagement between contact 25 and rotatable contact 26, due to the irregular surface of the latter. This intermittent engagement of these two contacts will energize contactor 16, thereby to complete a circuit to the small operating motor of the rheostat, which will rotate in such a direction as to cause nut 12 to move to the left, thereby to increase the resistance of the rheostat, and decrease the excitation of the field circuit of the exciter 6, and hence the excitation of the alternator 2. Due to the intermittent engagement of these contacts, the operation of the motor will be intermittent, thereby providing an effective anti-hunting means to prevent an over-running of the motor, and hence an over-running of the rheostat. Also, due to the fact that contact 26 is rotating, there will be a wiping action between the surfaces of contact 26 and contact 25, this action serving to keep the contacts clean whereby a minimum resistance is always ofl'ered to the flow of current between these contacts. Although I have shown contact 26 as a rotatable cam, it will be obvious to those skilled in the art that my invention is not limited to this precise arrangement, and that any equivalent means for producing a contact whose contactmaking surface moves periodically in the path of motion of contact 25 and which moves uniformly in a transverse direction to the motion from contact 25 could be employed without departing from my invention in its broader aspects. If the change in voltage on circuit 1 has been small, a few engagements of contacts 25 and 26 will suflice to change the excitation of machine 2 enough to restore the voltage to normal. It will be clear, however, that the greater the change in voltage on circuit 1, the greater the torque produced by motor 32, and hence the greater the pressure with which contact 25 is pressed against contact 26. Due to the resiliency of the mounting member 28, this will mean that contact 25 remains longer in engagement with contact 26, thereby increasing the average time the circuit of the operating motor is closed, and hence increasing the speed with which this motor changes the resistance in the exciter field circuit. The vibratory motion of contact 25 which is produced by its engagement with the cam 26, is transmitted by the resilient connection 28 to the movable means 30, and thence through means 40 to contact 37, thereby causing vibratory motion of this contact. If now the rise in voltage on circuit 1 is great enough, member 28 will be flexed enough to allow contact 37 to come into e11- gagement withmember 38, thereby completing the circuit for the operating coil of conall tactor 19, with the result that the short circuit around resistance 8 is opened, thereby suddenly inserting a comparatively large resistance in the field circuit of the exciter 7.

I This has the effect of-quickly reducing the excitation of the'exciter, and hence the excitation ofmachine 2. However, due to the fact that contact 37 has a vibratory motion,

the operation of contactor 19, will be intermittent, thus providing an effective anti-hunting I means for the quick acting portion of the regulator. If, however, the rise in voltage on circuit 1 is very great the force with which I again short-circuiting resistance 8, and sto citer great enough, contact 36 will engage contact ping the operating motor of therheostat. f the rheostat has not moved far enough to insert suificient resistance to compensate for the circuit changes causing the increase in voltage, the above described operation will again take place until the new value of the resistance of the rheostat is sufiicient to cause n'ormal voltage. It will thus be seen that the speed of operation of m regulator is de pendent upon the degree 0 change of the conditions to be regulated.

It now the voltageof circuit 1 is decreased, the torque of motor, 32 will be such as to cause contact .24 to engage contact 26, with the result that the operating motor of the.

rheostat is turned in the opposite direction, through the energization of contactor 17, thereb to decrease the resistance in the ex eld circuit. If the fall in yoltage is 38, thereby energizlng conta'c'tor 18 with the result that all of resistance 9 is short-circuited; thus suddenly removing a comparatively large resistance from the exciter field circuit, with the result that aquick increase in the excitation of the exciter, and machine 2 is produced. I

While I have shown and described a parhence of ticular embodiment of'my invention, it will be obvious to those skilled in the art that changes out eparting from my invention, and I,

therefore aim in the appended claims to cover all suc changes and modifications as fall within the true spirit and scope of my invention.

by Letters Patent of the United States is:

1. A regulating system comprising, in combination, a dynamo-electric machine, a circuit for controlling the field excitation of said machine, a slow-acting rheostat; in said and modifications may be made with- 'What I claim as new and desire to securecircuit a normally open short circuit. for said. rheostat, .a normally short. circuited resistance in said circuit, and means res onsive to increases and decreases of an e ectrical condition to be regulated for causing said'rheostat to respectively increase or decrease its resistance, said means being responsive to further increases and decreases of said condition for res ctively opening the short circuit across sai additional resistance or completing the short circuit about said rheostat. g T I 2. A regulating system comprising,in coinbination, a dynamo-electric machine, a circuit for controlling the field excitation of said machine, slow acting means for gradually changing the resistance of said circuit, quick actmg means for producing sudden. large changes in the resistance of said air cuit, means responsive to de artures from normal of an electrical condition to be regulated for actuating said slow acting means,- said condition responsive means being responsive to further departures from normal of said condition. for actuating said quick acting means, and anti-hunting'means for causing the action of said condltion res on- 'sive meansto be intermittent at a uni orm rate which is independent of the electrical condition of said dynamo-electric machine.

3. A regulating system having, in combination, a-dynamo-electric machine,a circuit for controlling the field excitation of said machine, a slow acting rheostat in said circuit,- a normally open short circuit for said 1 rheostat, a normally short circuited resistance in said excitation control circuit, means responsive to increases in the value of an electrical condition to be regulated for causin said rheostat to increase its resistance, said. means bein responsive to further increases in said con ition for opening the short circuit across said additional resistance, said means also bein responsive to decreases in the value of sai condition for causing said rheostat to decrease its resistance, said means in addition res ondingto-further decreases in thevalue 0 said condition for short circuiting said rheostat, and anti-hunting means associated with said condition responsive 11 means for causing its action to be intermittent; I 1 i 1 4, In combination, a circuit'whose resistance controls the field excitation of a dynamoelectric machine,'on.e of whose electrical conditions is to be re lated, aslow acti'n rheostat in said circuit, an additional resistance in said circuit, means normally short circuiting said resistance, means res onsive to variatrons in said electrical con 'tion for causing said rheostat to vary its resistance in a manner to cause theexcitation'of said machine to vary 's'oas to restore said condition. to normal, said means being nsive 'to furthe rchanges' in thezvalue of sa d concontrol means for producing relatively slow tion of said resilientl dition for causing said rheostat to be short circuited or for causing the short circuit about said additional resistance to be removed depending upon whether said condition is below or above normal respectively, and anti-hunting means for causing the action of said condition responsive means to be intermittent at a uniform rate which is in dependent of the amount of resistance in said excitation control circuit.

5. A regulating system comprising, a control circuit whose resistance controls the value of a condition to be regulated, electroresponsive means for slowly varying the resistance of said circuit, electroresponsive means for suddenly making large variations in the resistance of said circuit, means movable in accordance with departures of said regulated condition from a normal value, a pair of contacts mounted on said movable means, one of said contacts being resiliently mounted, a contact whose contact-making surface has a uniform periodic motion. in the path of motion of said resiliently mounted contact for connection therewith, a contact whose contact-making surface is stationary with respect to the path of movement of the other movable contact for cooperation there-. with, said movable contacts being so arranged that upon movement of said condition responsive means said resiliently mounted contact first engages its cooperating contact, whereby a vibrating motion is imparted to the other movable contact through the resilient mounting means, a circuit including said first-mentioned electroresponsive means and said first-mentioned pair of cooperating contacts, and a separate circuit including said second-mentioned electroresponsive means and said second-mentioned cooperating contacts.

6. An electrical regulator for cumulatively controlling two circuits which respectively and quick regulating changes comprising. means movable in accordance with changes in the magnitude of a condition to be regulated, a pair of contacts mounted thereon, one of said contacts being resiliently mounted, a contact cooperating with said resiliently mounted contact, the circuit controlling surface of said cooperating contact havmg a wiping motion transverse to the path of momounted contact and a uniform periodic vibratory motion in the path of movement of said resiliently mounted contact, a contact cooperating with the other movable contact, said contact havin a wiping motion transverse to the path 0 motion of the movable contact with which it cooperates, said contact being so arranged that upon movement of said movable means in response to changes in the regulated condition said resilient contact first engages its cooperating contact, whereby a vibratory motion is transmitted to the other movable contact through the resilient mounting means, and upon a further change in the regulated condition the said other movable contact intermittently engages its cooperating contact.

7. A voltage regulating system compris ing, a power circuit, a dynamo-electric machine for energizing said circuit, a field winding circuit for said machine, an exciter for said field circuit, a field circuit for said exciter, a rheostat in the exciter field circuit, a'

normally open short circuit around said rheostat, a normally short circuited a dditional resistance in said exciter field circuit, a contact in the form of a wheel with an uneven periphery, a second contact in the form of a wheel with a smooth periphery, means for rotating said contacts on their respective axes at a uniform speed, means movable in accord ance with departures of the voltage of said power circuit from a. predetermined normal value, a pair of resiliently mounted contacts on said movable means for respectively engaging the uneven periphery of said firstmentioned rotating contact depending upon Whether the voltage is above or below normal, a second pair of contacts on said movable means for respectively engaging the smooth periphery of said second-mentioned rotating contact upon further changes in the voltage above or below normal, circuits controlled by said resiliently mounted contacts when they engage their rotating cooperating contact for causing said rheostat to vary its resistance, and circuits controlled by said other movable contacts when they engage their rotating cooperating contact for respectively short circuiting said rheostat and opening the short regulated comprising, operating means including, relatively sensitive means for relatively slowly regulating said condition, relatively insensitive means for relatively quickly regulating said condition, and mechanical anti-hunting means associated with both said relatively sensitive and "said relatively insensitive means for causing their actions to be intermittent.

9. The combination with a machine, of means for regulating an operating condition of said machine, said means acting in response to relatively small variations in said condition to cause restoration of said condition in relatively small increments whose time durations vary in proportion to the amount of change of said condition, said means acting in response to relatively large variations in said condition to cause restoration of said condition in relatively large increments whose time durations vary in proportion to the amount of change of said condition.

10. The combination with a machine, of regulating means for an operating condition of said machine, said means acting on relatively small changes in said condition to cause relatively slow intermittent restoration of said condition in relativel small steps, said means acting to cause sai restoration to be more nearly continuous as larger changes in said cond1t1on occur, said means acting to cause relatively rapid intermittent restoration of said condition in relativel large steps when the variations in said con 'tion exceed a predetermined amount, and said meansacting to make said relatively rapid restoration continuous when the variation in said condition substantially exceeds said predetermined amount.

11. In an electrical regulator, a device for converting variations in a condition to be regulated into mechanical motion, a cam contact, a pair of resiliently mounted contacts operated by said device and arranged to respectively engage said cam contact upon relatively slight decreases or increases from a normal value of the regulated condition, a substantially circular contact wheel, a second pair of contacts operated by said device and arranged to respectively engage said circular contact wheel upon relatively large increases or decreases from a normal value of the regulated condition and means for rotating said cam contact and said wheel contact.

7 In witness whereof I have hereunto set my hand this 27th day of Au st 1930.

LOUIS TfioMPsoN. 

